Fluid converters



1 A. B. BARNES ETAL 3,014, 64

FLUID CONVERTERS Filed March 28, 1960 5 Sheets-Sheet 2- IO I J ,7, J8

FIG. 4.

//YAV x G Inventors:

AUSTEN B. BARNES b FRANCIS H.A.MEE

Dec. 26, 1961 A. B. BARNES ETAL 3,014,

FLUID CONVERTERS 5 Sheets-Sheet 3 Filed March 28, 1960 Inventors AUS'TENB. BARNES FRANCIS H.A.MEE

Dec. 26, 1961 Filed March 28, 1960 A. B. BARNES EI'AL FLUID CONVERTERS 5Sheets-Sheet 4 FIG- 8 Inventors AUSTEN B. BARNES FRANCIS H.A. ME'E WUMM1961 A. B. BARNES ET AL 3,014,464

FLUID CONVERTERS Filed March 28, 1960 5 sheets-sheet 5 85 a4 73 as a? 8a9 92 a3 78 Inventcrs AUSTEN B. BARNES FRANCIS H.A.MEE

United States Patent Ofliice 3,014,464 FLUID CGNVERTERS Austen BernardBarnes, Willowdale, Ontario, and Francis Herbert Arthur Mee, Aurora,()ntario, Canada, assignors to De Havilland Aircraft of Canada, LimitedFiled Mar. 28, 196i), Ser. No. 18,011

13 Claims. (Cl. 121-123) This invention relates to a fluid converter andmore particularly to means for converting energy from fluid underpressure into mechanical motion and further to means for pumping fluids.

It is amongst the objects of this invention to provide a converter ofsimple construction employing only two basic moving assemblies.

It is also amongst the objects of the invention to provide a doubleacting converter.

It is further amongst the objects to provide a converter in the form ofa motor capable of converting energy from fluid under pressure tomechanical motion.

It is still further amongst the objects of the invention to provide aconverter in the form of a double acting pump for fluids.

Further objects and advantages of the invention will become apparentfrom a consideration of the following description and the drawings, inwhich:

FIGURE 1 shows a cross-sectional view of a converter in the form of abasic embodiment of a motor in accordance with the invention;

FIGURE 2 shows a similar cross-section but with the valve and piston ina diiierent position;

FIGURE 3 shows a fractional cross-section of a modification to the formsof FIGURES 1 and 2;

FIGURE 4 shows a cross-sectional view of a motor incorporating variousself starting features;

FIGURE 5 shows a cross-sectional view illustrating a form of gascushioning employable with the invention;

FIGURE 6 shows a cross-section of a further embodiment of a converter inthe form of a motor in accordance with the invention;

FIGURE 7 showsa cross-sectional view along the lines 7-7 of FIGURE 6;

FIGURE 8 shows a cross-sectional view of a further embodiment of aconverter in the form of a motor in accordance with the invention; and

FIGURE 9 shows a crosssectional View of a converter in the form of apump in accordance with the invention.

Referring now to the drawings in which similar parts are given the samenumerical designation throughout and referring more particularly toFIGURE 1, there is shown a motor having an outer casing or cylinder 1%,piston 11, piston rod 12 and valve 13. Gas under pressure is introducedinto inlet port 14 and flows around the annular groove 15 in valve 13and thence into labyrinth passage 16, annular chamber 17, piston port 13and reaches the right hand end-200i cylinder 1i through passage 19,thereby forcing the piston 11 to the left. At the same time, gasentering inlet 14 and annular groove 15 passes through labyrinth passage21 to space 22 where it holds thevalve 13 hard against the piston 11,thereby keeping the port open as long as possible with the volume at 23being zero.

The piston moves toth'e left and as it does so the annular groove 15moves out of alignment with inlet port 14, and valve land 24 begins toblock inlet port 14. Gas or fluid is still capable of entering inletport 14 until valve land 24 completely closes the port. (See FIGURE 2.)At this stage the inertia of the piston 11 and the-continued expansionof the gas or fluid will cause the closing lip of land 24 to actuallypass the edge oi inlet port 14. In the case where a liquid is used, theinertia alone would be relied upon to eifect this part of the movement.This 3,014,464 Patented Dec. 26, 1961 can be accomplished by the Weightof the parts involved. As soon as this occurs, a small area of theannular groove 25 is momentarily exposed to the inlet pressure, and thegas or fluid will pass through annular groove 25 along labyrinth passage26 and begin to move the valve 13 to the left relative to the piston 11by introducing gas or fluid to 23. The piston 11 will at this time bealmost hard over to the left end of cylinder 10, and thus the valve 13is free to move under the influence "of gas or fluid proceeding throughlabyrinth passage 26 until the annular groove 25 is almost fully alignedwith the inlet port 14. Meanwhile the gas trapped in space 22 is free toescape via passage 21, annular groove 15 and outlet port 27, which ispositioned so that the annular groove 15 aligns with it as annulargroove 25 aligns with inlet port 14. Gas from annular groove 25 alsoenters labyrinth passage 28, and passes therefrom through annularchamber 29, port 30', and passages 31 and 32 into the left hand end 33of cylinder 10. This occurrence tends to move the piston 11 to the rightand the procedure described above for right-to-left movement isreversed. Upon the reverse operation, the gases which at this time wouldbe trapped in space 23 are exhausted through labyrinth passage 26,annular groove 25 and outlet port 34, which is positioned so as to bealigned with annular groove 25 when annular groove 15 is aligned withinlet port 14.

As the spaces at 22 and 23 are uncoupled from the spaces at 26 and 33,lower operating pressures may be employed inasmuch as the only load tobe overcome is that of the inertia and friction created by valve 13,plus a small reaction from the gas flow in the labyrinth passages andacross the lips of the ports. The gas flow in the valve may therefore berestricted by providing relatively narrow labyrinth passages at 21 and26. This provides a gain in operating economy. In order to providequieter operation and prevent metal to metal contacts, it is possible toprovide gas cushioning within the motor, as illustrated in FIGURE 5. Thebasic operation of the motor remains substantially as described withrespect to FIG- URE 1. Mechanical means such as springs-or resilientbuffer pads may of course be used as an alternative to the gascushioning cutaway portions shown in FIGURE 5, without departing fromthe scope of the invention.

By increasing the physical size of the motor while admitting the samequantity of gas or fluid, the gas or fluid may be expanded into agreater volume during the stroke than otherwise. Thus a more eflicientthermodynamic operating cycle can be obtained. A convenient manner oflimiting the gas charge is by restricting the size of the main inletport 14 with respect to the size of annular grooves 15 and 25. Such anarrangement is shown in the partial cutaway of FIGURE 3. Thisarrangement in eiiect provides an early cutoff for the inlet gases andallows them to expand subsequently.

Where the fluid to be used is liquid and where, therefore, there is noexpansion, all the inlet and valve passages would have to be openedfully to permit maximum flow. Apart from this, however, the motor wouldbe of the same form as shown in FIGURES l and2.

Referring now .to FIGURE 4, there are shown various ways of providingself-starting features for the motor. All that is required to ensureself-starting is to provide an unstabilizing force so that the solidshoulder or valve land 24 between grooves 15 and 25 can not remainperfectly aligned with the inlet port 14 during starting. One means ofproviding such an unbalanced force is by providing a spring 35 whichexerts an end thrust on valve 13 with respect to piston 11. As only avery weak spring is necessary, the operation of the valve 13 is notseriously affected. Another method is to provide gas bleedholes 36 in.annular shoulder or valve land 24. The holes 36 would have to be smallenough to give the elfect of a long time constant compared with thenormal valve operation, but their bleeding effect would be suflicient tocause the valve 13 to be moved slowly off centre if the high pressuregas was connected whilst land 24 was aligned with inlet port 14. Afurther alternative would be to provide a slight bevel or chamfer 37 tothe face 38 of valve land 24. It will be appreciated that whilst threemethods have been illustrated as examples in FIGURE 4, it is normallyonly necessary to incorporate on of these methods to provide aself-starting feature. Whilst the basic form and principles of the motorhave been described above, it will be appreciated that variousembodiments may be desirable for different purposes.

Referring now to FIGURE there is shown an example of a fully gascushioned embodiment of the motor referred to previously. Gas cushioningis obtained by the provision of shoulders 39 and 40 on the piston endsand corresponding cut-out portions 41 and 42 in the cylinder 10.Similarly, shoulders 43 and 44 may be provided on the valve 13 withcorresponding cut-out portions in the piston 11 so as to gas cushion thevalve 13 with respect to the piston 11.

Instead of routing the valving gas through ports cut in the valve, it ispossible to duct it through the motor case as shown in FIGURES 6 and 7.In this case, external passage 47 replaces labyrinth passage 21 of FIG-URE 1 and passage 48 replaces labyrinth passage 26 of FIGURE 1. Also, itis possible in using this embodiment of the invention to insert variablerestrictions 4-9 and 50 in the passages 47 and 48, thus facilitating thecontrol of the motors operating characteristics. In fact, an unbalancedoperation could be attained, if desired, by arranging a greaterrestriction in one passage than in the other.

It will be noted that inlet 14 and outlets 27 and 34 are positioned soas not to coincide with passages 47 and 48, and that they mayconveniently be disposed as shown in FIGURE 7, i.e. in a difierentportion of the cylinder casing 10. Apart from the positioning ofpassages 47 and 48 in this manner the operation of the motor remainssubstantially described with respect to FIGURE 1.

FIGURE 8 shows another embodiment of a motor of the invention. Theoperation is as follows:

Fluid under pressure is admitted through inlet port 51 to annular groove52, passes therefrom via labyrinth passage 53 into annular chamber 54.At the same time, fluid under pressure is communicated via annulargroove 52 and labyrinth passage 55 to the space (initially zero) 59 atthe left hand end of the valve 13, thereby forcing the valve 13 to theright relative to piston 11 until annular groove 52 is fully alignedwith inlet port 51. At this point, annular passage 54 and piston port55a are in full communication, allowing fluid to pass through passage 56to end chamber 57 where it exerts pressure on the end wall of cylinderand thereby moves the piston 11 to the left. Fluid within space 60 willat first escape via outlet 61 until the end piece 62 of piston 11effects closure thereof. Similarly end piece 63 of piston 11 will atfirst expel fluid from space 64 via outlet 65. As outlets 61 and 65 areclosed, the fluid trapped in space 64 provides automatic cushioning.

Eventually the piston 11 is pushed to the left until the annular groove52 has passed inlet port 51, and the expanding gas or fluid continues tomove the piston 11 such that a small area of the annular groove 66 ismomentarily exposed to the inlet pressure, and the gas or fluid passesalong labyrinth 67 and begins to move the valve 13 to the left (withinthe confines of the piston end pieces 62 and 63), byv filling volume 60.As the piston 11 is at this time almost hard over at the left hand endof the cylinder, the valve 13 moves over until annulus 66 is almostfully aligned with inlet port 51. The gas trapped at 59 escapes via exitport 65.

Gas from 66 also enters labyrinth 68 and annular chamber 69, and thenflows through the piston port 70 and along passage 71, entering space 64and pushing the piston 11 to the right. The piston 11 carries the valvealong with itself as in the right-to-left movement.

At the end of the stroke, the gas at 64 finally exhausts via 65 as thelatter becomes uncovered by the receding piston.

It will be noted that in FIGURE 8 the annular chambers 54 and 69 are ofreduced length and are arranged so that annular chambers 54 and 69 andpiston ports 55a and 70, respectively, are only communicative when thevalve 13 is sufficiently offset relative to the piston 11 as to ensurepositive valve operation, with little or no bounce or flutter. It is, ofcourse, possible, by increasing the length of annular chambers 54 and69, to make them permanently communicate'with piston ports 55a and 70 ina manner similar to the porting arrange ment shown in the other figures.

FIGURE 9 shows a pump for pumping liquids which is generally similar tothe motors previously described, but operates from a source ofreciprocating mechanical motion. If the piston 11 is moved to the leftfrom the position shown, it slides through the valve 13 until pisftonport 72 is aligned with annular valve chamber 73. When the piston port74 is in alignment with annular valve chamber 75, the piston 11 beginsto drag the valve 13 to the left, the right hand shoulder 76 of thepiston 11 being in contact with the right hand end 77 of valve 13. Asthe valve and piston move to the left, the volume in chamber 78 formedbetween the cylinder 10 and the valve and piston assembly increases,while the cor responding volume in chamber 79 at the other end de'-creases. The drop in pressure at 78 induces fluid to flow via inlet port80, valve annulus 81, labyrinth passage 82, annular valve chamber 75,piston port 74 and passage 83 to chamber 78. Fluid in chamber 79 isforced via valve port 84, passage 85, and port 72 into annular valvechamber 73. From thence it passes by passage 86 to annulus 87 and outthrough outlet 88.

0t the end of the stroke, the outlet port 88 is closed by the centralvalve land 89, whilst the inlet port is closed by the right hand endland 90 on valve 13. This effect constitutes a fluid lock and, althoughit need not be completely attained, it is essential that it beapproached. When the piston 11 reverses and begins to move to the right,because of the fluid lock or near blockage of the inlet and outlet ports80 and 88, respectively, the valve lags the piston movement instead ofbouncing with it, as might occur if the outlet were at high pressure andconnected with chamber 79 by 87, 86, 73, and 72. Also the pressuretransient formed in chamber 78 by the initial right hand movement itpiston 11 contributes to the valve lag.

As the piston 11 moves to the right, the piston port 72 communicateswith valve chamber 75, and the increasing volume at 79 draws fluid frominlet port 80 via annulus 81 and passage 82 communicating with chamber75. Similarly, piston port 74 connects with valve chamber 91, and thedecreasing volume at 78 causes exhaust via 83, 74, chamber 91 andlabyrinth passage 92, which communicates with annulus 87.

The reverse stroke from the right hand end is similar, except that theinlet port 80 is closed by central valve land 89, and the outlet port 88is closed by the left hand end valve land 93. Valve lag in this case isaided by decrease in pressure at 78 and momentary increase at 79.

Whereas various embodiments of the invention have been shown, showingdesirable features for'different circumstances, these same circumstanceswill dictate whether or not it is desirable to use, for example, gascushioning, an unbalanced arrangement, early cut-off, etc. Additionally, a self-contained vibrator motor may be made by the simpleexpedient of deleting the power takeoff shaft 12 and by fixing the bodyof the cylinder directly to the load.

It will therefore be appreciated that variations and modifications canbe made without departing from the spirit and scope of the invention asdefined by the following claims.

What we claim is:

1. A fluid convertor in the form of a motor comprising a double endedcylinder; a double acting piston slidable within said cylinder anddividing said cylinder into chambers at either end thereof; end piecesof a predetermined thickness on said piston and of a diameter equal tothat of said cylinder; a portion of reduced diameter between said endpieces; inlet port and outlet port means disposed inwardly from the endsof said cylinder a distance at least equal to the thickness of each endpiece; a cylindrical valve piece axially slidable upon said reducedportion of said piston; conduit means in said piston in the form of aseparate passage extending from each end of said piston to a separateport on said reduced portion of said piston; conduit means in said valvepiece alignable with said ports on said reduced portion of said piston;annular groove means on the exterior of said valve piece communicatingwith said conduit means in said valve piece and alignable with saidinlet and outlet port means in said cylinder, thereby to efiectcommunication between said inlet port means and one of said chambers andbetween said outlet port means and the other of said chambers; and landmeans on said valve piece whereby, upon relative movement of said pistonand said valve piece, said communication between said port means andsaid chambers may be successively blocked and reversed.

2. A system for converting the energy from fluid under pressure intomechanical power, comprising in combination: a cylindrical casingembodying, intermediate of the ends thereof, inlet port means and outletport means therein, in substantially diametrically opposed location, onefrom the other; a double acting piston member slidably reciprocablewithin said casing, having substantially cylindrical flange portions ateither end thereof, and a portion of reduced diameter extendingtherebetween, and embodying combined inlet and outlet ports and passagestherein; and a cylindrical valve member coaxially mounted upon saidreduced portion and adapted to move in relation thereto between theinner faces of said flange portions, said valve member having aplurality of land portions thereon adapted successively to block and toopen said inlet port means and said outlet port means, said valve memberembodying, on the outer periphery thereof, annular grooves, on the innerperiphery thereof, annular passages in communication with said combinedinlet and outlet ports and passages, between each said annular grooveand one of said annular passages, labyrinth passages, and between eachsaid annular groove and one of said inner faces of said flange portions,restricted labyrinth passages.

3. The system claimed in claim 2 in which at least one end of saidpiston member is in driving engagement with an output shaft extendingthrough said casing in coaxial alignment with said reduced portion.

4. The system claimed in claim 2 and further comprising self-startingmeans whereby said inlet port means in said casing is at least partiallycommunicable with one of said combined inlet and outlet ports andpassages in said piston member at all times.

5. A system for converting the energy from fluid under pressure intomechanical power, comprising in combination: a cylindrical casingembodying an inlet port therein equidistantly disposed from the endsthereof and a pair of outlet ports therein equidistantly disposed fromsaid ends and in diametrically opposed location from said inlet port; adouble acting piston member slidably reciprocable within said casing,having substantially cylindrical flange portions at either end thereof,and a portion of reduced diameter extending therebetween, and embodyingcombined inlet and outlet ports and passages therein; and a cylindricalvalve member co-axially mounted upon said reduced portion and adapted tomove in relation thereto between the inner faces of said flangeportions, said valve member having end land portions and a central landportion thereon, said central land portion being disposed intermediateof said end land portions and being adapted co-operably with said endland portions, successively to block and to open said inlet port and atleast one of said outlet ports, said valve member embodying, on theouter periphery thereof, annular grooves on either side of said centralland portion, on the inner periphery thereof, annular passages incommunication with said combined inlet and outlet ports and passages,between each said annular groove and one of said annular passages,labyrinth passages, and between each said annular groove and one of saidinner faces of said flange portions, restricted labyrinth passages.

6. The system'claimed in claim 5 in which said inlet port and saidoutlet ports are of like size and said central land portion is of a sizesufiicient to block said inlet port completely.

7. The system claimed in claim 5 in which said inlet port is ofrestricted size with respect to that of said outlet ports and of saidannular grooves on the outer periphery of said valve member.

8. The system claimed in claim 5 and further comprising self-startingmeans whereby said inlet port means in said casing is at least partiallycommunicable with one of said combined inlet and outlet ports andpassages in said piston member at all times.

9. The system claimed in claim 8 in which said selfstarting means is inthe form of a bleed hole embodied in said central land portion andcommunicating said inlet port with one of said labyrinth passages insaid valve member.

10. The system claimed in claim 8 in which said selfstarting means is inthe form of a slight bevel on the face of said central land portion,whereby said inlet port is at least partially communicable with one ofsaid annular grooves in said valve member at all times.

11. The system claimed in claim 5 in which said flange portions haveshoulders extending from the outer faces thereof in axial alignment withsaid reduced portion, and said casing embodies corresponding cut-outportions at either end thereof.

12. The system claimed in claim 11 in which said end land portions onsaid valve member have shoulder portions extending therefrom, and saidinner faces of said flange portions embody corresponding cut-outportions therein.

13. The system claimed in claim 5 in which said end land portions onsaid valve member have shoulder portions extending therefrom, and saidinner faces of said flange portions embody corresponding cut-outportions therein.

References Cited in the file of this patent UNITED STATES PATENTS109,167 Ambos Nov. 15, 1870 271,781 Brazelle Feb. 6, 1883 397,958 BarthFeb. 9, 1889 612,437 Rhodes Oct. 18, 1898 705,436 Pecoraro July 22, 1902926,260 Klein June 29, 1909

